From: Heiner Kallweit hkallweit1@gmail.com
mainline inclusion from mainline-v5.1-rc1 commit 124eee3f6955f7aa19b9e6ff5c9b6d37cb3d1e2c category: bugfix bugzilla: NA CVE: NA
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When bringing down the netdevice (incl. detaching it) and calling netif_carrier_off directly or indirectly the latter triggers an asynchronous linkwatch event. This linkwatch event eventually may fail to access chip registers in the ndo_get_stats/ndo_get_stats64 callback because the device isn't accessible any longer, see call trace in [0].
To prevent this scenario don't check for IFF_UP only, but also make sure that the netdevice is present.
[0] https://lists.openwall.net/netdev/2018/03/15/62
Signed-off-by: Heiner Kallweit hkallweit1@gmail.com Tested-by: Geert Uytterhoeven geert+renesas@glider.be Reviewed-by: Florian Fainelli f.fainelli@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Reviewed-by: Weiwei Deng dengweiwei@huawei.com Reviewed-by: Zhaohui Zhong zhongzhaohui@huawei.com Reviewed-by: Yonglong Liu liuyonglong@huawei.com Signed-off-by: You Shengzui youshengzui@huawei.com Reviewed-by: YueHaibing yuehaibing@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/core/link_watch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/link_watch.c b/net/core/link_watch.c index e38e641e98d5b..7f51efb2b3ab9 100644 --- a/net/core/link_watch.c +++ b/net/core/link_watch.c @@ -155,7 +155,7 @@ static void linkwatch_do_dev(struct net_device *dev) clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state);
rfc2863_policy(dev); - if (dev->flags & IFF_UP) { + if (dev->flags & IFF_UP && netif_device_present(dev)) { if (netif_carrier_ok(dev)) dev_activate(dev); else